"Swim Like the Sharks", Input/Output, ME Departments, May 2004

input/output

by Jean Thilmany,
Associate Editor

Swim Like the Sharks

You've heard of the fastest gun in the West. But, what about the fastest swimsuit in the world?

Described by its manufacturer as just that, the Speedo Fastskin FSII is said to reduce passive drag in the water by as much as 4 percent compared with the Speedo suits used at the last Summer Olympic Games, in Australia. It's what can come of mixing engineers and sharks.

Passive drag affects a swimmer in the streamline position, usually after the initial dive into the water and following a turn. During a 50-meter race, a swimmer is likely to be in the streamline position for up to 15 meters.

Fastskin FSII, the result of four years of research and development, has undergone the most advanced testing and analysis that Speedo has applied to a swimsuit. The product could make the difference between a gold medal and fourth place, the company said. Designers at the manufacturer's research and development headquarters, dubbed the Aqualab, used computational fluid dynamics technology to design the swimsuit. The Speedo brand name is licensed by the Pentland Group of London.

Speedo researchers put their new swimsuit under CFD analysis to better understand how to optimize the flow of water around the swimmer.

Speedo researchers said that, as far as they can tell, CFD engineering technology has never been used to develop swimwear, although it's commonly used in other sports, such as auto racing and yachting. (There's more on that in this month's Computing department.) The company expects swimmers to don the racing suit for the Summer Olympics held in Athens this year.

Research started with a study of the shark, to examine its skin texture and movement through water. The study, in conjunction with the Natural History Museum in London, led to the discovery that the shape and feel of the shark's denticles—small, pointed surface projections—vary along its body to manage the flow of water.

Researchers used those findings to create the original Fastskin, a swimsuit that mimics the skin of a shark. Swimmers from more than 130 countries wore that suit at the Sydney Olympics. Its wearers won more than 80 percent of the swimming medals and set 13 out of 15 world records, Speedo executives said.

The Speedo Fastskin FSII is said to reduce passive drag in the water by as much as 4 percent compared with the Speedo suits used at the last Summer Olympic Games, in Australia.

But the manufacturer wanted to go one better. It put the findings of the shark study under CFD analysis, and created a one-piece suit that uses different fabrics on different parts of the body to optimize the flow of water around the athlete. This is different from the original Fastskin suit, which used the same fabric throughout. The new swimsuit is a full bodysuit contoured to every curve. It brings to mind the latest X-Men movie and, indeed, Speedo designers say they asked Hollywood costume makers for tips.

The company created, for the first time, male- and female-specific and stroke-specific swimsuits.

In developing the suit, researchers created a virtual swimmer to wear it. The swimmer was a computer model and, as designers created new designs for the suit, they could use CFD software to predict drag and fluid flow around a human figure as it moved through water. The company used CFD software from Fluent Inc. of Lebanon, N.H. It helped researchers design a hydrodynamic suit engineered around the drag and fluid flow characteristics of competitive swimmers. By using different fabrics on different parts of the body, researchers were able to optimize the flow around an athlete, mimicking the skin of a shark.

Look for the new swimsuits to be stretched over the forms of the world's fastest swimmers at this summer's Athens Olympic Games, including 18-year-old Michael Phelps of Baltimore. Phelps, who won four gold medals at the 2003 World Championships while breaking five world records, will try to match Mark Spitz's record of seven Olympic gold medals. If Phelps is successful, Speedo will pay him $1 million.